In Chemical Pharmaceutical Bulletin, 1972, vol. 20, No. 10, pp. 2191-2203, 3-(2-allylphenoxy)-6-chloro-4-methoxypyridazine has been disclosed but a 3-phenoxy-4-pyridazinol compound having a hydroxyl group at the 4-position of the pyridazine has not been disclosed, and there is no description about a herbicide.
In Journal of the Chemical Society: Perkin Transaction I, 1975, No. 6, pp. 534-538, 3-(2-hydroxyphenoxy)-4-methoxypyridazine and 6-chloro-3-(2-hydroxyphenoxy)-4-methoxypyridazine has been disclosed but a 3-phenoxy-4-pyridazinol compound having a hydroxyl group at the 4-position of the pyridazine has not been disclosed, and there is no description about a herbicide.
In U.S. Pat. No. 5,559,080, a 3-(phenoxy which may be substituted)pyridazine compound having a haloalkyl-phenoxy group at the 4-position of the pyridazine has been disclosed but a 3-phenoxy-4-pyridazinol compound having a hydroxyl group at the 4-position of the pyridazine has not been disclosed. Also, in the 3-(phenoxy which may be substituted) pyridazine compound having a haloalkylphenoxy group at the 4-position of the pyridazine, an oxygen atom bonded to the 4-position of the pyridazine is bonded by a benzene ring, and its herbicidal activity was insufficient.
Also, at present, a number of herbicides have been practically used as a herbicide for a paddy field, and widely been used for general purpose as a single agent and a mixed agent. However, there are many kinds of paddy field weeds, and germination and growth period of the respective weeds are not uniform, in particular, occurrence of perennial weeds ranges for a long-period of time. Thus, it is extremely difficult to prevent from and kill all weeds with one time spread of a herbicide. Accordingly, as a herbicide, an appearance of a chemical which can kill many kinds of weeds including annual weeds and perennial weeds, that is, which has a wide weed-killing spectrum, is effective for already grown weeds, preventing and killing effects of weeds of which can be maintained for a certain period of time, and has high safety to paddy rice has earnestly been desired.
Also, as upland herbicides, a number of herbicides have now been commercially available and practically used, but there are many kinds of weeds to be prevented, and occurrence thereof ranges for a long period of time, so that a herbicide which has higher herbicidal effects, has broad weed-killing spectrum, and causes no chemical damage to crops has been desired.
One of the effective ingredient of the herbicidal composition of the present invention (hereinafter referred to as a second herbicidally active compound), 4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5-pyrazolyl-p-toluenesulfonate [hereinafter referred to as Compound A. General name: Pyrazolate], 2-[4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy]acetophenone [hereinafter referred to as Compound B. General name: Pyrazoxyfen], 2-[4-(2,4-dichloro-m-toluoyl)-1,3-dimethylpyrazol-5-yloxy]-4′-methyl-acetophenone [hereinafter referred to as Compound C. General name: Benzofenap], 5-cyclopropyl-1,2-oxazol-4-yl α,α,α-trifluoro-2-mesyl-p-tolyl ketone [hereinafter referred to as Compound D. General name: Isoxaflutole], 2-(2-chloro-4-mesylbenzoyl)cyclohexan-1,3-dione [hereinafter referred to as Compound E. General name: sulcotrione], 2-(4-mesyl-2-nitrobenzoyl)cyclohexan-1,3-dione [hereinafter referred to as Compound F. General name: mesotrion] and 4-chloro-2-(methylsulfonyl)phenyl 5-cyclopropyl-4-isoxazolyl ketone [hereinafter referred to as Compound G. General name: Isoxachlortole] are each conventionally known herbicidal compound, and each described in The Pesticide Manual 11th Edition, pp. 1049 to 1050, Ibid. pp. 1054 to 1055, Ibid. pp. 111 to 112, The Pesticide Manual, 12th Edition p. 563, Ibid. p. 848, Ibid. p. 602 and EP 470 856 (1990). These compounds have high effects against annual broad-leaved weeds and a part of perennial weeds, but their effects against rice plant weeds or a part of perennial weeds are not necessarily sufficient.